1. Field of the Invention
This invention relates to magnetic recording and reproducing head arrangements, and especially to dispositions or configurations of magnetic heads in the head assembly of a multi-head magnetic disk or tape memory device of the moving-head type which realizes recording of information with high track density by utilizing the azimuth recording method.
2. Description of the Prior Art
As one of the conventional methods which realize high track density recording, one could mention the azimuth recording method which is utilized, for example, in video tape recorders. In video tape recorders utilizing this method, a magnetic tape is wound around a rotational head cylinder and is helically scanned by two magnetic heads included therein which have different gap azimuths, or directions of the head gaps, with respect to the direction of width of the recording tracks on the tape. In this way, this method realizes a high track density recording without the need for the inter-track blank regions which, otherwise, must be disposed between the recording tracks for the purpose of prevention of interference or "cross-talk" between the tracks. The azimuth recording method is characterized by the prevention of cross-talk between the adjacent tracks by the effect of azimuth loss in the process of reproduction. This effect results from the fact that the recording and reproduction on adjacent tracks are carried out by the magnetic heads which have different gap azimuths, and therefore magnetizations formed on the adjacent tracks are caused to have different directions. Thus, recording without inter-track regions becomes possible, with the recording tracks disposed closely adjacent to or partly overlapping each other.
The present invention is concerned with a multihead, moving-head system which is utilized, for example, in magnetic disk memories utilizing the azimuth recording method. The head assembly of a magnetic disk memory is held at rest when the tracks are being tracked by the magnetic heads, and is moved in steps in the direction of the radius of the disk to change the tracks to be tracked by the heads. A magnetic disk memory device utilizing the azimuth recording method is disclosed, for example, in Japanese Laid-Open Patent Application No. 120415/1978. The device according to this patent application comprises a flying head assembly including therein two magnetic heads which oppose the surface of the magnetic disk. The two magnetic heads having different gap azimuths are disposed in and held by the head assembly in such a way that the centers of the gaps of the magnetic heads are separated by the track pitch of the disk in the radial direction of the disk, and also in the circumferential direction thereof by a predetermined distance necessary to prevent magnetic interference between the two magnetic heads. This configuration or disposition of the magnetic heads in the head assembly has resulted in the problem that a slight alignment error of the head assembly with respect to the magnetic disk causes the adjacent tracks recorded by the two magnetic heads to overlap each other, thereby occasioning cross-talk or complete obliteration of information. Another disadvantage of the device according to the above patent application results from the fact that the lower face of the flying head assembly which maintains a slight separation from the disk surface during the rotation of the disk is inclined downwardly in the direction of rotation of the disk with respect to the disk surface, and thus has a greater separation at one magnetic head than at the other. This difference between the spacings of the two magnetic heads from the disk surface has resulted in the disadvantage that the recording and reproducing characteristics of the two magnetic heads are completely different.
These problems or disadvantages become more serious when more than two magnetic heads are mounted in a single head assembly and the circumferential distance between the two outermost magnetic heads becomes greater.